A strange new trend gripped Brussels on Thursday. Call it Macron-mania.

For his debut appearance in Brussels as French president, Emmanuel Macron unleashed a sort of feverish excitement not seen since Britain voted to leave the European Union or the darkest days of the Greek debt crisis.

Journalists tussled over a microphone to ask him questions. Statesman lobbied hard for a sit-down meeting, however short.

But this time the dominant emotion in Brussels was not fear or anxiety at some looming EU collapse. It was hope, at least for old Europe.

"Today the emphasis was on optimism," said German Chancellor Angela Merkel, adding that the summit had focused on "critical developments" for the EU instead of crisis management.

On the up

Compared to countless EU summits plagued by Greece's debt crisis, a migrant influx, Brexit and a populist surge that nearly brought the house down, the change in tone was striking.

For the first time in years, members of the EU establishment could rejoice. The leader of a major member state, fresh from winning a convincing majority in parliament, was in town broadcasting plans to revive the union and strengthen its foundations in partnership with Germany.

"I think Macron is a very clever man, at ease with other heads of state, heads of institutions," said European Parliament President Antonio Tajani. "I think I've found a major counterpart on the most important matters — immigration, the fight against terrorism, industrial and trade policy."

He added, for good measure: "I think he can play an important role in Europe."

French President Emmanuel Macron, German Chancellor Angela Merkel and British Prime Minister Theresa May, in Brussels

As Macron himself pointed out at a packed press conference that — because the summit had gone so uncharacteristically smoothly — had started early, his devotion to the EU was neither new, nor unknown to French voters. "I campaigned on this idea," he said, referring to his pro-EU agenda.

Now that he was president, Macron said he wanted to use his first EU Council summit to "define or redefine a Europe that protects". This, he said, meant reforming the bloc to make populations feel more secure against terrorism, climate change, unfair wage competition and trade "dumping" from beyond EU borders.

As proof of his commitment, he pointed to plans to create an EU defense fund and a "permanent cooperation structure" for military joint procurement — ideas for which he repeatedly thanked European Commission President Jean-Claude Juncker in a rare nod from a national leader.

Asked whether he thought France or the European Union was more difficult to reform, Macron dodged. "There will be anger," he said. "But I see that the French voted twice for this agenda of change. I think that Europe is also ready for this."

It seemed that not even Brexit, the other theme of the day, could puncture Macron's optimism. "It's a good signal to open exchanges on that subject [citizens' rights]", he said.

An EU diplomat gave Macron's first steps a thumbs up: “Macron is definitely showing up at a good time, as the only thing that matters in Brussels is will and determination."

Trade trepidation

Behind the excitement, however, was trepidation among states worried that Macron's vision will not work for them.

If Macron gets his way on trade, and the EU imposes tougher anti-dumping rules, won't Sweden, the Netherlands and other free-trading nations stand to lose economically?

The president was ready with an answer. "I met with the Dutch prime minister, and he came to agreement with me on this idea of protection ... because he also had to face populism in his country," said Macron. "I am not for protectionism; I am for reasonable openness."

Among central and Eastern European states, his plans for a "two-speed Europe" were also causing jitters, as leaders worry about becoming second-class members.

French President Emmanuel Macron at the EU Council headquarters | Leon Neal/Getty Images

Here again, Macron was ready with an anecdote: In a one-on-one meeting, Bulgaria's president admitted to him that even his country had a problem with wage competition from foreigners illegally entering the country, Macron said.

The message: If they're not on board the Macron train yet, they will be.

However, skepticism on his ability to bridge all divides still shone through on the summit's sidelines.

"Does he want to show off to the media with his lack of goodwill toward central European countries, or does he want to speak frankly," Beata Szydło Poland's prime minister told local media. "I think it's good to discuss facts, and not rely on some stereotypical insights."

Hungary's prime minister, Viktor Orbán, lashed out at Macron for saying in an interview that some countries were treating the EU as a "supermarket". "Criticizing the central European countries is not the best way to express friendship."